pumping of concrete mixtures rheology lubrication layer Related Information

Report No. K-TRAN: KSUKefid Best Practices for Concrete

deliver concrete from the mixing truck to the formwork. Although concrete pumping has been used to place concrete since the 1960s, there is still a lack of exact knowledge supported by research evidenceas to what affects concrete pumpability and how pumping changes concrete properties.

"Changes in fresh properties of flowable concrete induced

The results showed that the fresh concrete properties are affected in diverse ways by pumping, with the results being dependent on the concrete fresh properties, and pumping parameters. Additionally, an attempt was performed to reverse engineer the composition of the so called 'lubrication layer' through the science of rheology.

China Hzs60 Concrete Batching Plant Machine,Concrete

China Concrete Mixer, Concrete Mixer Manufacturers

Parameters influencing pressure during pumping of self

The lubrication layer facilitates the pumping of concrete through pipes. If no lubrication layer could be formed, the pumping pressure would be significantly higher to pump the concrete at the same discharge rate. Some authors take the effect of the lubrication layer into account by introducing a slipping or sliding velocity [18, 19, 24, 30, 31].

Pumping of concrete mixtures: rheology, lubrication layer

Pumping of Concrete Mixtures: Rheology, Lubrication Layer Properties and Pumping Pressure Assessment Pumping is the most utilized placement technique to deliver fresh concrete from the concrete mixer to the formwork on construction site.

HZS60 Concrete Batching Plant

Yicheng HZS60-240 Belt Batching Plant makes the maximum productivity to 60-240 cubic meter per hour. The batching plant adopts a modular structure that can be assembled and disassembled rapidly using common hardware. This makes it convenient to move.

Investigations on the Influence of Binders toward

Mar 03, 2020 · The lubrication layer of concrete plays a vital role in the pumping of concrete. In the present study, the influence of different types of binders ordinary portland cement (OPC), Portland pozzolana cement (PPC), portland slag cement (PSC), and solid volume fraction on the flow properties of the lubrication layer (cementitious pastes) corresponding to 3 grades (M30, M40, and M50) of concrete

Rheological Control of 3D Printable Cement Paste and Mortars

• Printed Mixtures = • Rheology during induction period controlled by availability of discontinuity in deposited layer t = 80 min • Pumping challenges caused several missed layers at beginning of print. Printing Mix C t = 12 min • Locally high shear rates produce lubrication layer • Fully developed flow • J=0 plug flow; J=3 2

"Changes in fresh properties of flowable concrete induced

The results showed that the fresh concrete properties are affected in diverse ways by pumping, with the results being dependent on the concrete fresh properties, and pumping parameters. Additionally, an attempt was performed to reverse engineer the composition of the so called 'lubrication layer' through the science of rheology.

DigitalConcrete 2018 | Pumping

However, for modern concrete mixtures the accuracy of traditional design charts is questioned. Based on a better understanding of the flow of the material in the pumping pipe, including the behavior of the lubrication layer near the pipe surface, shortcomings of traditional design charts can be overcome.

Material and Equipment Considerations In Concrete Pumping

Friction is a major consideration in pumping and an adequate amount of water is required.Presence of a motar film at the walls of pipes also enhances lubrication. A higher percentage of cement is beneficial for concrete pumping. The size and shape of aggregate as well as presence of air in the mixture interferes with effective pumping of the

A Review on the Pumping Behavior of Modern Concrete

flow rate of concrete mixture is larger, the pumping pressure is higher. Then the shear stress near the inner wall of the pump pipe may exceed the yield stress of the fresh concrete. In addition to the formation of lubrication layer and block zone, the fresh concrete will also form a shear zone between block zone and lubrication layer.

Pumping of Fresh Concrete: Insights and Challenges | RILEM

Nov 25, 2016 · Pumping of fresh concrete is of utmost importance for concrete practice. Required pumping pressures are typically estimated based on design charts. However, with the increased use of chemical admixtures and the development of more flowable concrete mixtures, the accuracy of traditional design charts is questioned. In recent years, significant progress has been obtained in …

How do concrete rheology, tribology, flow rate and pipe

Lubrication layer properties during concrete pumping

Effect of lubrication layer on velocity profile of

Jan 22, 2015 · The rheology of concrete is predominant for the required pressures in a pumping pipe. However, more detailed information is required on the formation and the properties of the lubrication layer near the pipe surface, in order to be able to accurately predict the pressure-discharge relation. By means of experimental research in combination with advanced numerical simulations, the lubrication

3D Concrete Printing: A Systematic Review of Rheology, Mix

When printable concrete is pumped through a pipe, the flow of concrete is divided into two layers as lubrication layer and bulk concrete due to the particle migration. The rheology of both layers is different, and the pumping requirement for a printable concrete mix depends on the combined yield stress and plastic viscosity of both layers.

Lubrication layer properties during concrete pumping

Pumping of concrete is impossible without the formation of a lubrication layer [22,23]. The shear-induced particle migration, the bleeding tendency of concrete, and the wall effect were considered

Viscoelastic Properties of Fresh Cement Paste to Study the

Jun 28, 2016 · During concrete pumping, the migration and redistribution of particles occur in a pipe and the lubrication layer that forms between the bulk concrete and the pipe wall is the governing factor determining the flow behavior. In order to identify flow behavior of pumping, in this study, the viscoelastic properties related to the microstructural behavior of a flocculated suspension were examined

Viscoelastic Properties of Fresh Cement Paste to Study the

Keywords: concrete pumping, lubrication layer, dynamic oscillatory measurement, viscoelastic. 1. Introduction Concrete pumping involves the flow of a complex fluid under high pressure in a pipe, and thus predicting flow behaviors of concrete pumping is challenging research area. For the characterization and prediction of the flow of con-

Pumping of fresh concrete : insights and challenges - CORE

However, with the increased use of chemical admixtures and the developent of more flowable concrete mixtures, the accuracy of traditional design charts is questioned. In recent years, significant progress has been obtained in understainding the flow of the material in the pumping pipe, including the behavior of the lubrication layer near the